Case Study: Anticoagulation Flashcards
What are the main uses of blood thinners?
Prevent thrombus formation in the venous circulation
What is prothrombin time used for?
DOACs
= blood test for thinning
What is INR used for?
Warfarin
What are the anticoagulants in the UK?
Warfarin
Apixaban
Rivaroxaban
Edoxaban
dabigatran
What do vitamin K antagonists do?
Inhibit the vitamin K dependent clotting factors
What are the vitamin K dependent clotting factors?
II
VII
IX
X
What is an example of a vitamin K antagonist?
Warfarin
What are the DOACs?
Apixaban
Edoxaban
Rivaroxaban
Dabigatran
What does Apixaban, Edoxaban + Rivaroxaban do?
Direct + reversible inhibitors of factor Xa
What does dabigatran do?
Reversible inhibitor of free thrombin
What are the risk factors of indication for DOACs?
Age >75 years
Hypertension
Diabetes
Symptomatic HF
What are the contraindications for DOACs?
Active bleeding
Acute stroke
GI bleeding
Intracranial bleeding
Family history
Which anticoagulant is there NOT a reversible agent for?
Edoxaban
What are the different monitoring requirements for Warfarin?
INR
TTR
Reassess suitability
Describe INR
Target range for indication
How often are INR done?
When newly on it
= every week
What is TTR?
Total time in range
What is the INR range for most things?
2.0-3.0
What is the target INR for most things?
2.5
What are the exceptions to the normal INR range?
Mechanical valves in mitral position
Anti-phospholipid Ab syndrome
= 2.5-3.5
What do anticoagulation patients have to carry?
Yellow book
= shows drug, dose, monitoring
What is INR NOT used for?
DOACs
What monitoring for DOACs are required pre-treatment?
Baseline clotting screen
U&Es
LFTs
FBCs
Why does kidney function need to be assessed before DOAC use?
Drugs renally excreted
What assesses the risk of clotting?
CHA2DS2-VASc score
What assesses the risk of bleeding?
ORBIT score
What is the anticoagulation male score for CHA2DS2-VASc?
1 or more
What is the anticoagulation female score for CHA2DS2-VASc?
2 or more
What is in the CHA2DS2-VASc?
CHF = 1
Hypertension = 1
Age >75 = 2
Diabetes = 1
Stroke = 2
Vascular Disease = 1
Age 65-74 = 1
Sex (female) = 1
What is the low risk ORBIT score?
0-2
What is the medium risk ORBIT score?
3
What is the high risk ORBIT score?
4-7
What is in the ORBIT score?
Older age >74 = 1
Reduced haemoglobin = 2
Bleeding history = 2
Insufficient kidney function = 1
Treatment with antiplatelets = 1
What are the advantages of DOACs?
Lower intracranial haemorrhage + stroke risk
Reduced monitoring
Fewer drug + food interactions
Less variable dosing
What are the disadvantages of DOACs?
Higher cost
NO reversible agent for Edoxaban
Increased risk of GI bleed
Caution with renal impairment
What are the advantages of Warfarin?
Lower cost
Easily reversed
Reputable history
What are the disadvantages of Warfarin?
Frequent monitoring
Drug + food interactions
Variable dosing
When do you NOT offer anticoagulation?
When patient aged under 65 with AF + NO risk factors other than their sex
When does Warfarin need to be taken?
At night
When does rivaroxaban need to be taken?
With food
What do you counsel the patient about with Warfarin?
Don’t massively change your diet
= can affect INR score
What should you never do if you miss a dose?
Double up on a dose
What are some signs of bleeding?
Blood in urine or stool
Blood in sputum
Blood in emesis
Bleeding that not resolved or slowing within 10 mins
What are some signs of clotting?
Chest or unilateral leg pain
SOB
Elevated HR (>100bpm)
Unilateral lower extremity swelling
